He was later identified, as is standard in DOJ investigations especially where a suspect could be in jeopardy from terrorists, when the investigation was completed. That investigation found:
Specifically, the investigation revealed no evidence to establish that, at the time the officer fired a single shot at Ms. Babbitt, the officer did not reasonably believe that it was necessary to do so in self-defense or in defense of the Members of Congress and others evacuating the House Chamber.
Your characterization of the investigation as somehow creating an unjustified cloak of secrecy is false. DOJ generally does not share details of ongoing investigations. Especially where domestic terrorist acts are concerned.